JPH09208220A - Method for preventing solidification of ammonium thiocyanate during storage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent solidification of ammonium thiocyanate during storage by drying a ammonium thiocyanate crystal to decrease the water content and then housing the crystal in a bag comprising a bag having specified permeability of water vapor and a craft paper bag. SOLUTION: An ammonium thiocyanate crystal prepared by crystallization is dried to decrease the water content to <=0.5%. The dried ammonium thiocyanate crystal is housed and stored in a bag comprising a bag having <=10g/m<2> .24Hr permeability of water vapor and a craft paper bag. The bag having specified permeability of water vapor consists of a composite film bag or a laminated bag of an Al foil and a moisture-preventing film. Thereby, absorption of water from air during storage is almost prevented. Since the permeating rate of the air in the bag to the outside due to the load given downward on the bag is small, the load on the ammonium thiocyanate crystal is decreased and solidification of the ammonium thiocyanate crystal can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing solidification during storage when ammonium thiocyanate (alias: rhodammone) crystals are packed and stored.

[0002]

2. Description of the Related Art Ammonium thiocyanate is a monoclinic system colorless foliate or columnar crystal which is stable at room temperature.
Change to orthorhombic at temperatures above ℃. The specific gravity is 1.305 and the melting point is 149 ° C. However, it changes to thiourea at around 140 ° C., so it is difficult to measure. Decomposes at 200-300 ° C into ammonia, carbon dioxide and hydrogen sulfide. Rapid heating to 250 ° C produces melam and melamine thiocyanate. Some deliquescent in moist air. Easily soluble in water, soluble in ethanol, acetone, pyridine, liquid ammonia and liquid sulfur dioxide.

The applications of ammonium thiocyanate are synthetic resins, hydrogen peroxide stabilizers, dyeing aids, photographs, fertilizers, herbicides and the like. As the packing of ammonium thiocyanate, a cheap polyethylene bag + kraft paper bag is generally used. Ammonium thiocyanate packed in a polyethylene bag + kraft paper bag absorbs moisture from the atmosphere due to the high water vapor transmission rate of the polyethylene bag, and ammonium thiocyanate itself has a water content of about 1%. It solidifies after storage for about a week. When ammonium thiocyanate solidifies in the bag,
Crushing is required again at the time of use, labor for crushing is required, powder is scattered around during crushing, which causes corrosion of equipment, and ammonium thiocyanate may be added during the reaction depending on the degree of crushing. When charged into a reactor equipped with a stirrer, a collision impact on the stirrer causes problems such as damage to the device.

As a method for preventing moisture absorption and solidification during storage of fertilizers having deliquescent property, the powder itself is completely dried or a moisture-proof coating is applied. Also,
As for the external environment, it is considered to store it in a place having a humidity control function or to completely package it.

[0005]

However, complete drying of ammonium thiocyanate crystals requires a considerable economic burden, and even if completely dried, they are stored in a polyethylene bag + kraft paper bag after being packaged. Therefore, it is impossible to prevent solidification due to moisture absorption from the air. In addition, the complete packaging method can prevent moisture absorption from the air, but it is solidified by the moisture held by ammonium thiocyanate itself and the load from the top when loaded and stored, and the complete packaging Has the disadvantage that it is too costly.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a method for preventing solidification during storage of ammonium thiocyanate in a bag which can prevent solidification during storage.

[0007]

According to the present invention, the ammonium thiocyanate crystals are dried to reduce the water content to 0.5% or less in order to prevent solidification when the ammonium thiocyanate crystals are packed in a bag and stored. After that, water vapor transmission rate 10g
/ M ² · 24 Hr or less and the kraft paper bag is packed and stored. in this way,
By storing in a bag composed of a kraft paper bag and a bag having a water vapor transmission rate of 10 g / m ² · 24 Hr or less, there is almost no moisture absorption from the air during the storage period, Since the rate at which air in the bag escapes due to the load from the upper part is slow, the load applied to the ammonium thiocyanate crystal is reduced accordingly, and the solidification of the ammonium thiocyanate crystal is prevented.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION According to the method for preventing solidification during storage of ammonium thiocyanate of the present invention, ammonium thiocyanate crystals produced by a crystallization operation are dried to obtain a water content of 0.5.
% Or less, then water vapor transmission rate 10 g / m ² · 2
It is packed and stored in a bag composed of a bag of 4 hours or less and a kraft paper bag for storage. By storing in this way, there is almost no moisture absorption from the air during the storage period, and moreover, the rate at which the air in the bag escapes due to the load from the top during the storage period is slow, so the ammonium thiocyanate crystals The load is reduced accordingly and the solidification of ammonium thiocyanate crystals is prevented.

In the present invention, the ammonium thiocyanate crystals are dried to a water content of 0.5% or less when the water content of the ammonium thiocyanate crystals exceeds 0.5%.
Even if there is no moisture absorption from the air outside the bag, it solidifies during storage due to the water content of ammonium thiocyanate,
This is because the above purpose cannot be achieved.

The water vapor permeability of the bag inside the kraft paper bag used in the present invention is measured in accordance with the test method specified in ASTM E-96. Unit: g / m ² · 24 Hr
It is represented by. In the present invention, the water vapor transmission rate of the bag inside the kraft paper bag used for bagging the ammonium thiocyanate crystals is set to 10 g / m ² · 24Hr or less because the water vapor transmission rate exceeds 10 g / m ² · 24Hr. This is because the ammonium thiocyanate crystals are solidified by moisture absorption from the air, and the above object cannot be achieved.

[0011] The following bag water vapor transmission rate 10g / m ² · 24Hr, long or less water vapor transmission rate 10g / m ² · 24Hr, but are not limited to, moisture cellophane on one or both surfaces of an aluminum foil, polyethylene, Aluminum bag laminated with polypropylene (A
l)), or a composite film bag such as polypropylene laminated on one or both sides of polypropylene, nylon laminated on one or both sides of polypropylene or polyethylene, or laminated on one or both sides of vinylidene chloride with polypropylene or polyethylene. Can be used.

[0012]

【Example】

Example 1 Water vapor permeability inside a three-layer kraft paper bag: 16-22
Polyethylene (PE) single bag of g / m ² · 24 Hr, same polyethylene (PE) double bag and water vapor transmission rate: 0 g
Ammonium thiocyanate crystal 20 in each of aluminum bags (Al bags) in which polyethylene is laminated on both sides of an aluminum foil of 1 / m ² · 24 Hr.
Each bag was packed with 5 kg, the air in the bag was degassed, the mouths of the polyethylene bag and the aluminum bag were welded, and then the bag was sewn and sealed with a sewing machine to obtain a test sample. As shown in FIG. 1, the hardness index transition study is performed by placing the test sample 2 on the pallet 1, placing the pallet 3 on the pallet 3, and placing the ammonium thiocyanate bag 4 5 on the pallet 3.
0 bags (1000 kg) were loaded and stored, and the hardness index survey was conducted every 2 or 3 days until 15 days later (8/21 to 9/5). The results are shown in Table 1 and FIG. The water content of each test sample was measured at the time of bagging and after 15 days from bagging, and the ammonium thiocyanate crystals were uniformly taken from each bag. Table 2 shows the results. The hardness index in Table 1 is the same as that immediately after being packed. 2: Especially soft (the shape of the bag changes when the bag is held), 3: Soft (the shape of the bag is difficult to change, but when pressed with a finger) The shape is broken. 4: A little hard (it doesn't deform even if you push it with your finger, but it deforms when you put your weight on it) 5: It's fairly hard (you can't loosen the bag without dropping it on the floor) did. In addition, the conditions at the time of collecting samples for moisture measurement are as follows: when packing, weather: sunny, place: ammonium thiocyanate room, after 15 days,
Weather: Sunny, Location: Ammonium thiocyanate Warehouse was inside.

[0013]

[Table 1]

[0014]

[Table 2]

As shown in Table 1 and FIG. 2, in the polyethylene single bag and the polyethylene double bag, the solidification of ammonium thiocyanate crystals progressed rapidly, and the hardness index which is a standard for shipment after 5 days from bagging. I've exceeded three.
In addition, the state of ammonium thiocyanate at the time of sampling after the lapse of 15 days was solidly solid. On the other hand, in the aluminum bag, the progress of consolidation was slow, and the hardness index was 2 even after 15 days, which was below the standard for shipment. The state of ammonium thiocyanate at the time of sampling after 15 days had not solidified at all, and was a smooth powder.

As shown in Table 2, the water content of ammonium thiocyanate was 0.03 to 0.1 on average in the single bag of polyethylene and the double bag of polyethylene after bagging and after 15 days.
5% more. On the other hand, there was almost no difference between the aluminum bag and the bag after 15 days. This is considered to be due to the influence of the water vapor permeability of the polyethylene bag.

Example 2 Water vapor permeability inside the three-layer kraft paper bag: 16 to 22 g
/ M ² · 24Hr polyethylene single bag, water vapor transmission rate: 4.5g / m ² · 24Hr vinylidene chloride composite film bag laminated with polyethylene on both sides and water vapor transmission rate: 0g / m ² · 24Hr aluminum foil Each of the bags made of aluminum bags (Al bags) laminated with polyethylene on both sides is packed with 20 kg of ammonium thiocyanate crystals, 5 bags each, and after welding the mouths of the polyethylene bag, the composite film bag and the aluminum bag, When the mouth of the kraft paper bag was sewn and sealed with a sewing machine, a bag in which the air inside the bag was degassed and a bag in which air was intentionally introduced were prepared as test samples. As shown in FIG. 3, the hardness index transition survey was performed by placing the test sample 2 on the pallet 1, placing the pallet 3 on the pallet 3, and loading the four drums 5 (1000 kg) on the pallet 3. Store and store hardness index survey every 2 or 3 days after 15 days (9
/ 11 to 9/26). The results are shown in Table 3 and FIG. Also, during bagging and after 15 days of bagging,
The water content was measured for each sample in which ammonium thiocyanate crystals were uniformly taken from each bag. The results are shown in Table 4. In addition, the hardness index in Table 3 is the same as that immediately after being packed. 2: Particularly soft (the bag shape changes when the bag is held), 3: Soft (the bag shape is difficult to change, but when pressed with a finger) The shape is broken. 4: A little hard (it doesn't deform even if you push it with your finger, but it deforms when you put your weight on it) 5: It's fairly hard (you can't loosen the bag without dropping it on the floor) did. In addition, the conditions at the time of collecting the sample for measuring the water content were as follows: when packing in a bag, weather: sunny, location: ammonium thiocyanate room, after 15 days, weather: cloudy, location: ammonium thiocyanate warehouse. .

[0018]

[Table 3]

[0019]

[Table 4]

As shown in Table 3 and FIG. 4, polyethylene 1
In the heavy bag, the solidification of ammonium thiocyanate crystal progressed remarkably fast, and the hardness index 3 which can be shipped exceeded 3 days after the bag was packed, and the hardness index 5 reached 11 days later, and 15 days passed. The state of the ammonium thiocyanate crystal at the time of sampling after passing was solidly solid. Although the composite film bag exceeded the shipping standard value of hardness index 3, the hardness index was not larger than 3.5 even after 15 days, and the hardness index was similar to that of the aluminum bag. The state of the ammonium thiocyanate crystal at the time of sampling after the lapse of 15 days was not solidified at all, and was a smooth powder. In the aluminum bag, the solidification of ammonium thiocyanate crystals proceeded slowly, and the hardness index was 3 even after 15 days, and the hardness index 3 of the shipping standard value was cleared. Further, the state of ammonium thiocyanate crystals at the time of sampling after 15 days had not been solidified at all and was a dry powder.

As shown in Table 4, the water content of ammonium thiocyanate increased by an average of 0.05% after 15 days in a single polyethylene bag, and the maximum solidified portion was 0.5.
%, It was confirmed that the composite film bag and the aluminum bag hardly increased after 15 days.

[0022]

According to the method of the present invention, the ammonium thiocyanate crystal is dried to reduce the water content to 0.5% or less, and then the bag is made up of a kraft paper bag and a bag having a water vapor transmission rate of 10 g / m ² · 24 Hr or less. By packing in a bag and sealing and storing the bag, moisture absorption from the air into the bag is significantly suppressed, and it is possible to prevent solidification during storage of ammonium thiocyanate.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of sample stowage positions used in a change survey of hardness index in Example 1.

FIG. 2 is a graph showing the relationship between the number of days elapsed and the hardness index in the hardness index transition study of Example 1.

FIG. 3 is an explanatory diagram of sample stowage positions used in a hardness index transition study in Example 2;

FIG. 4 is a graph showing the relationship between the number of days elapsed and the hardness index in the hardness index transition study of Example 2.

[Explanation of symbols]

 1, 3 Pallets 2 Samples for testing 4 Ammonium thiocyanate bag packing 5 Drums

Claims (2)

[Claims] 1. A method for preventing solidification during storage of ammonium thiocyanate, wherein ammonium thiocyanate crystals produced by a crystallization operation are dried to reduce the water content to 0.5% or less, and then the water vapor transmission rate is 10 g / m ² ·. 24H
A method for preventing solidification during storage of ammonium thiocyanate, which comprises bundling a bag composed of a bag having a size of r or less and a kraft paper bag for storage. 2. The solid in the storage of ammonium thiocyanate according to claim 1, wherein the bag having a water vapor transmission rate of 10 g / m ² · 24 Hr or less is a composite film bag or a bag in which a moisture-proof film is laminated on an aluminum foil. How to prevent binding.